Recently, I looked up the June 22, 1907 edition of the Toronto Globe. I discovered that older newspapers have very interesting ads, as they are (a) very wordy, and (b) not necessarily constrained by the principle of truth in advertising.
For example, there were two ads for electric belts. I’m not sure exactly what they did – apparently, not much – but the ads suggested that they did a whole lot of wonderful things. Here’s the first one:

And here’s the other:

I looked these fine gentlemen up in the online Toronto city directories, and discovered that neither Dr. Sanden nor Dr. McLaughlin appear to have actually been real people.
The city directory for 1908 lists the Sanden Electric Company at the 6 Temperance Street address, with the proprietor being F. H. Curtis (later replaced by W. E. Burkholder). This company appeared in the 1917 city directory, but there was a fire in the Dineen Building that year, which may have driven it out of business, as I could not find it after that.
The 1908 city directory also has a listing for the Doctor McLaughlin Company, managed by a gentleman named Ira C. Olmstead. The firm had moved to 237 Yonge by 1912, and was gone by 1917.
If you want to learn more about the history of electric belts, this article in the Atlas Obscura web site is for you. It shows that the Sanden and McLaughlin companies were actually Canadian branches of firms based in the United States, as it contains U.S. ads for both belts. The article mentions that ads for belts became less common after 1910, as the American Medical Association began to crack down on this sort of thing.
The BBC has a more general article on the history of self-electrification as a Victorian-era therapeutic tool.